Archived posting to the Leica Users Group, 2015/07/14
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]I was surprised to see in the manual that there was lossless compression of the DNG. So I thought I?d try it out by taking two shots, one compressed and one uncompressed. When I looked at my DNG file, I was astounded to find a DNG of over 40 MB and a compressed one of about half that size. (I deleted the negatives before thinking of writing this, so I can?t give you exact numbers. Well, I was at first astounded that lossless compression could be that effective. Then I thought about the details of an image. Except where there is really fine structure in the image, there will be areas where the data does not change. A simple number triple, one giving a value for, say the red pixel, the second giving a starting location in the file, and the the third the number of consecutively stored pixels having the same value, could easily result in a factor of two compression for lots of pictures. And what I just described is a very unsophisticated compression method. If anyone knows more about how this might have been done, I?d be very interested. kanner at acm.org 650-326-8204 Question authority and the authorities will question you.